1. Field of the Invention
The present invention relates to an apparatus for transferring lead frame from a container thereof during semiconductor assembly process.
2. Description of the Prior Arts
Assembly of semiconductor begins with a die bonding process in which semiconductor chip formed with a desired circuit pattern is electrically connected to a lead frame. Lead frame shapes a semiconductor package, electrically connects chip to external terminals, and dissipates heat generated from the chip.
Usually, lead frames are stacked in a container (or stacker) when supplied by a manufacturer. A buffering material such as paper is interposed between lead frames in order to prevent a bend of leads of lead frame which may occur by a shock during transportation or handling, which eventually result in wire bonding failures. When transferring lead frame from the container to a die bonding guide rail, which carries lead frame to die bonding machine, it is required to remove individual lead frame from the container.
FIGS. 1 through 4 show a conventional apparatus and process for removing lead frame from a container.
With reference to FIG. 1, a plurality of lead frames (12) are stacked in a container (10), and papers as a buffering material is interposed between the lead frames. An apparatus (30) for transferring lead frame from container thereof comprises a guide bar (16) provided with vacuum pads (17), to which either of lead frame or paper is adhered by vacuum suction.
The overall process of transferring lead frames from the container to a die bonding guide rail shall be described hereinafter.
First, guide bar (16) provided with vacuum pads (17) moves down as indicated by arrow 1 until its vacuum pads contact uppermost lead frame (12) in the container (10) ("step 1"). Then, a vacuum suction machine (not shown) applies a vacuum suction to the pads (17) so that the uppermost lead frame (12) can adhere to the pads (17). And, the apparatus (30) carrying a lead frame goes up ("step 2").
With now reference to FIG. 2, the apparatus (30) carrying a lead frame is moved to a die bonding guide rail (18) to transfer the lead frame thereto ("step 3"). Now the apparatus (30) is located above the rail (18). Thereafter, the apparatus (30) goes down toward the rail (18) and drops the lead frame (12) ("step 4") upon elimination of vacuum suction, and goes upward ("step 5").
With now reference to FIG. 3, the apparatus (30) returns to its original location ("step 6"), and moves down until its vacuum pads contact uppermost paper (14) in the container (10) ("step 7"). Then, a vacuum suction to the pads (17) so that the uppermost paper (14) can adhere to the pads (17). And, the apparatus (30) carrying a paper goes up ("step 8").
With now reference to FIG. 4, the apparatus (30) carrying a paper is moved to a paper container (20) to transfer the paper thereto ("step 9"). Then, the apparatus (30) is operated in the same manner as that of transferring lead frame. That is to say, the apparatus (30) goes down toward the paper container (20) and drops the paper (14) ("step 10") upon elimination of vacuum suction, and goes upward ("step 11"). And, the apparatus (30) returns to its original location ("step 12").
As described above, the conventional apparatus and process for transferring a couple of a lead frame and a paper from container consists of 12 steps in total, which is a relatively time-consuming process.
Further, the conventional apparatus and process have an another drawback that when picking up a lead frame, the subsequent paper just beneath the lead frame is also picked up by an action of electricity.